From 02139162f541bb56ddbaf0a2d6142256a0454372 Mon Sep 17 00:00:00 2001 From: Miklos Vajna Date: Thu, 10 Nov 2016 11:55:07 +0100 Subject: digital signatures: briefly document OOXML/PDF signing effort It may be unexpected for users to see that OOXML files are always only partially signed. Change-Id: Ie7c6c553580a4eb38ed72c8a50b75f4b7902613f --- source/text/shared/guide/digital_signatures.xhp | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/source/text/shared/guide/digital_signatures.xhp b/source/text/shared/guide/digital_signatures.xhp index 514852d491..eb85aef7bb 100644 --- a/source/text/shared/guide/digital_signatures.xhp +++ b/source/text/shared/guide/digital_signatures.xhp @@ -87,7 +87,10 @@ Signatures and software versions The signing of contents got changed with OpenOffice.org 3.2 and StarOffice 9.2. Now all contents of the files, except the signature file itself (META-INF/documentsignatures.xml) are signed. - When you sign a document with OpenOffice.org 3.2 or StarOffice 9.2 or a later version, and you open that document in an older version of the software, the signature will be displayed as "invalid". Signatures created with older versions of the software will be marked with "only parts of the documents are signed" when loaded in the newer software. + When you sign a document with OpenOffice.org 3.2 or StarOffice 9.2 or a later version, and you open that document in an older version of the software, the signature will be displayed as "invalid". Signatures created with older versions of the software will be marked with "only parts of the document is signed" when loaded in the newer software. + When you sign an OOXML document, then the signature will be always marked with "only parts of the document is signed". Metadata of OOXML files are never signed, to be compatible with Microsoft Office. + When you sign a PDF document, then this marking is not used. Signing only parts of the document is simply an invalid signature. + Signing other document formats is not supported at the moment. When you load an ODF document, you might see an icon in the status bar and the status field in the dialog that indicates that the document is only partially signed. This status will appear when the signature and certificate are valid, but they were created with a version of OpenOffice.org before 3.2 or StarOffice before 9.2. In versions of OpenOffice.org before 3.0 or StarOffice before 9.0, the document signature was applied to the main contents, pictures and embedded objects only and some contents, like macros, were not signed. In OpenOffice.org 3.0 and StarOffice 9.0 the document signature was applied to most content, including macros. However, the mimetype and the content of the META-INF folder were not signed. And in OpenOffice.org 3.2, StarOffice 9.2, and all versions of LibreOffice all contents, except the signature file itself (META-INF/documentsignatures.xml), are signed. Security Warnings When you receive a signed document, and the software reports that the signature is valid, this does not mean that you can be absolutely sure that the document is the same that the sender has sent. Signing documents with software certificates is not a perfectly secure method. Numerous ways are possible to circumvent the security features. -- cgit v1.2.3